Transmission properties of microwave in rectangular waveguide through argon plasma

To study the impact of plasma generated by microwave breakdown on the propagation properties of microwave in high power microwave (HPM) devices, a three-dimensional (3-D) fluid model of argon plasma slab in rectangular waveguide is established and calculated by the finite-difference-time-domain (FDTD) method. A rectangular waveguide with a breakdown chamber filled with argon is set as the physics model, and HPM with frequency of 3-50 GHz propagates through this physics model. The time evolutions of the breakdown process are investigated, the reflection, transmission, and absorption coefficients of HPM are calculated, and the influences of some important parameters, including the thickness of the plasma slab and the microwave frequency on the propagation properties of the microwave are shown. Results of this work can offer theoretical instructions for suppressing the influence of breakdown to the performance of HPM devices, and for the use of microwave breakdown, such as the design of plasma limiter or absorber in HPM devices.